There has been long-standing concern on the part of parents or guardians as to the content of programs watched by children and minors. This concern has been long-standing with respect to televisions and, more recently, with respect to on-line services such as, those provided through service providers, e.g., America Online, or through other electronic means of text and image-based communication.
Various attempts have been made to limit access by children to subject matter that is deemed inappropriate. Certain locks simply block specific channels, where those channels are either known to or are suspected to carry programming which is deemed unacceptable for viewing by children. Other systems incorporate time-based limitations, for example, where the entire television may not be used during certain hours. Typically, the set time limits would preclude operation of the system during “bedtime” hours or at times when parental supervision does not exist, e.g., after school hours. Yet other lock systems serve to make the entirety of the system unavailable other than to authorized users.
Various attempts have been made to provide more refined lock systems. One attempt, the so-called “V-chip” system, utilizes a coding system indicative of content. For example, a given show may be designated as including adult language, violence or nudity. These indicators are often provided by single letter designators, such as L, V and N, respectively. Other coding systems analogous to movie rating codes, such as G for general audience, PG for parental guidance, R for restricted, etc., may also serve as a censor-based assessment of the content. These content-based designators are carried in television systems over the extended data service (XDS or EDS) system. The adopted standard for NTSC television is the EIA-608 standard. Information which is typically carried in such systems includes the network name, show title, and brief description of the contents of the show. There are currently proposals to include rating information of the type previously mentioned in the XDS data.
FIG. 1 shows a typical format of EIA-608 standards as a function of time. Initially, a horizontal sync pulse 10 initiates a pulse train. A color burst pulse 12 follows the horizontal sync pulse, and is typically provided for all line scans. Next, a clock run-in-signal 14 serves as a synchronizing signal. A sequence of start bits 16, labeled S1, S2 and S3 follow. As depicted, the pulse train here is shown with pulse S3 being “high” and S1 and S2 being “low.” In the extended data service system, various characters are then provided. Character one 18 is composed of bits (labeled B0, B1, B2, B3, B4, B5 and B6) and a parity check bit 22 (labeled P1). Character two 24 is composed of bits (labeled B0, B1, B2, B3, B4, B5, B6 and B7) and a parity check bit 26 (labeled P2) for the byte of character two 24. Typically, the XDS data is carried on a line, which is not visible on the television display, such as line 21.
FIG. 2 shows a schematic drawing of the prior art “V-chip” system. A television or other display 30 is the ultimate recipient of display information. Initially, some source of information such as a television signal 32 is supplied from any number of sources, such as over-the-air transmission, cable or other recorded source. Channel selection 34 controls the tuner 36 to select the desired information from television signal 32. The output of tuner 36 is an audio/video signal 38 corresponding to the channel selected. A data slicer 40 is coupled to the output of the tuner 36. The data slicer 40 functions to monitor the XDS signal as carried in the audio/video signal 38. The data slicer 40 may either strip the XDS signal from the audio/video signal 38 or simply duplicate the XDS signal. With the “V-chip” system, the XDS data obtained by the data slicer 40 is program rating information. The program rating information is supplied from the data slicer 40 to the comparator 42. A list 44 of prohibited ratings is stored or provided. Typically, the system would identify all prohibited ratings by level, such as R and X, though a system could utilize logic to prohibit any rating at a given level or above (the convention above meaning more mature or more likely to be prohibited). In the event of coincidence between the output of the data slicer 40 comprising the rating data of the program and the list of prohibited ratings 44, the comparator 42 provides a blocking signal 46 to signal blocking mechanism 48. The signal blocking mechanism 48 functions as a switch, blocking or otherwise scrambling audio/video signal 38, such that the show having the prohibited rating is not displayed.
A problem with the current “V-Chip” systems is that these systems are apparently not as user-friendly as the FCC had hoped. For example, the user must typically select, not only a television rating and/or movie rating, but also one or more subject matter categories (e.g., L, V, N), requiring that the user negotiate several menus within the menu system of the television. Adding to the complexity is the FCC requirement that the subject matter categories and ratings are interdependent. That is, only certain subject matter categories are selectable given a selected television or moving rating. Thus, a simpler implementation of a V-Chip system is desired.